Technical Field
The present invention relates to photovoltaic devices, and more particularly to devices and methods having improved quality of transparent electrodes without compromising performance.
Description of the Related Art
Photovoltaic devices include transparent conductive electrodes on a front side that permit radiation to pass therethrough. Transparent conductive electrodes may include indium-tin-oxide (ITO). ITO is typically used to form the transparent conductive electrode of heterojunction (HJ) solar cells on crystalline Si (c-Si). High-quality ITO is typically polycrystalline and requires substrate temperatures higher than 150° C. during growth. These formation temperatures may have detrimental effects on hydrogenated amorphous silicon (a-Si:H) and may compromise the quality of the a-Si:H as a result of hydrogen loss from a-Si:H or at the a-Si:H/c-Si interface due to out-diffusion.
In addition, post-deposition annealing can compromise the a-Si:H/c-Si interface quality due to mechanical strain induced by the structural change in ITO during crystallization. In addition, post-deposition annealing may negatively impact a-Si:H or the a-Si:H/c-Si interface due to the loss of hydrogen.